dorsal/arxiv
View SchemaChiral SU(3) dynamics and $\Lambda$-hyperons in the nuclear medium
| Authors | N. Kaiser, W. Weise |
|---|---|
| Categories | |
| ArXiv ID | nucl-th/0410062 |
| URL | https://arxiv.org/abs/nucl-th/0410062 |
| DOI | 10.1103/PhysRevC.71.015203 |
| Journal | Phys.Rev.C71:015203,2005 |
Abstract
We present a novel approach to the density dependent mean field and the spin-orbit interaction of a $\Lambda$-hyperon in a nuclear many-body system, based on flavor-SU(3) in-medium chiral perturbation theory. The leading long-range $\Lambda N$-interaction arises from kaon exchange and from two-pion exchange with a $\Sigma$-hyperon in the intermediate state. The empirical $\Lambda$-nucleus potential depth of about $-28 $MeV is well reproduced with a single cutoff scale, $\bar \Lambda = 0.7 $GeV, effectively representing all short-distance (high-momentum) dynamics not resolved at scales characteristic of the nuclear Fermi momentum. This value of $\bar\Lambda$ is remarkably consistent with the one required to reproduce the empirical saturation point of isospin-symmetric nuclear matter in the same framework. The smallness of the $\Lambda$-nuclear spin-orbit interaction finds a natural (yet novel) explanation in terms of an almost complete cancellation between short-range contributions (properly rescaled from the known nucleonic spin-orbit coupling strength) and long-range terms generated by iterated one-pion exchange with intermediate $\Sigma$-hyperons. The small $\Sigma\Lambda$-mass difference figures prominently in this context.
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"abstract": "We present a novel approach to the density dependent mean field and the\nspin-orbit interaction of a $\\Lambda$-hyperon in a nuclear many-body system,\nbased on flavor-SU(3) in-medium chiral perturbation theory. The leading\nlong-range $\\Lambda N$-interaction arises from kaon exchange and from two-pion\nexchange with a $\\Sigma$-hyperon in the intermediate state. The empirical\n$\\Lambda$-nucleus potential depth of about $-28 $MeV is well reproduced with a\nsingle cutoff scale, $\\bar \\Lambda = 0.7 $GeV, effectively representing all\nshort-distance (high-momentum) dynamics not resolved at scales characteristic\nof the nuclear Fermi momentum. This value of $\\bar\\Lambda$ is remarkably\nconsistent with the one required to reproduce the empirical saturation point of\nisospin-symmetric nuclear matter in the same framework. The smallness of the\n$\\Lambda$-nuclear spin-orbit interaction finds a natural (yet novel)\nexplanation in terms of an almost complete cancellation between short-range\ncontributions (properly rescaled from the known nucleonic spin-orbit coupling\nstrength) and long-range terms generated by iterated one-pion exchange with\nintermediate $\\Sigma$-hyperons. The small $\\Sigma\\Lambda$-mass difference\nfigures prominently in this context.",
"arxiv_id": "nucl-th/0410062",
"authors": [
"N. Kaiser",
"W. Weise"
],
"categories": [
"nucl-th"
],
"doi": "10.1103/PhysRevC.71.015203",
"journal_ref": "Phys.Rev.C71:015203,2005",
"title": "Chiral SU(3) dynamics and $\\Lambda$-hyperons in the nuclear medium",
"url": "https://arxiv.org/abs/nucl-th/0410062"
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